An Unusual Case of Vulvar Involvement in the Course of Granulomatosis with Polyangiitis.

Granulomatosis with polyangiitis is a rare autoimmune disease with the presence of c-ANCA in most cases. It involves necrotizing inflammation in small and medium-sized vessels with multiple granulomas. The disease can affect many systems, but the typical triad of attacked systems are the upper and lower respiratory tracts and kidneys, with varying degrees of severity. Involvement of the respiratory tract may manifest, among other symptoms, as nasal crusting, nosebleeds, and dyspnea. Among patients with granulomatosis with polyangiitis, only less than 1% develop genitourinary system involvement. We present a case study of a 36-year-old woman with an 8-year-long GPA history and a lesion, which, due to its appearance and accompanying symptoms, aroused the suspicion of a neoplasm but was proven to be a granuloma with a nontypical location. The systemic disease was treated with glucocorticosteroids and cyclophosphamide. The lesion on the labium minus was surgically removed. We concluded that the macroscopic picture of GPA of the vulva and vulvar cancer is similar. The patient's medical history may help differentiate GPA and vulvar cancer. Although vulvar GPA is extremely rare, it should be considered in the differential diagnosis of vulvar lesions, especially those suspected to be oncological.